Lucy Harper, 17, a high school junior who lives in College Station, Texas, has been picking at her skin for as long as she can remember. When she was in seventh grade, she also started pulling out her hair.

“For a while my skin picking was under the radar, but it was because I was pulling my hair,” she says. “If I wanted my skin to clear up, I’d stop picking and start pulling. If I wanted my hair to grow back, I’d stop pulling and start picking.”

She lost so much hair that her middle school classmates asked whether she was going bald. “I tried everything to stop picking and pulling,” she says. “I bought tons of fidget toys. I tried constraining my arm with a wrist brace. I got permission to wear gloves and a hat to school, and I even once went to piano lessons with Band-Aids on every one of my fingertips.”

Harper suffers from trichotillomania (hair pulling) and excoriation (skin picking, also known as dermatillomania), two of several disorders collectively known as body-focused repetitive behaviors. The umbrella term includes a number of repetitive “self-grooming” habits that can cause damage or injury through pulling, picking or scraping, or biting the hair, skin and nails.

Many people engage to some extent in nail biting or skin picking. But when these behaviors become extreme and out of control, they are regarded as serious disorders.

“There is significant psychosocial damage,” says Douglas Woods, a professor of psychology at Marquette University who studies these conditions. Among those who can’t contain the urge to pick, pull or bite, “depression is relatively common. People become very self-conscious, and self-esteem suffers. They start to avoid social situations in which people could notice the effects of their behavior, and often spend tremendous amounts of time trying to cover the effects.”

Historically, such behaviors had been considered impulse-control disorders, along with kleptomania and gambling addiction. However, in the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders, body-focused repetitive behaviors are categorized as obsessive-compulsive disorders. “The truth is, they probably belong in an in-between category,” Woods says.

Although now regarded on the same spectrum, the two actually are quite different. Classic OCD occurs when someone experiences uncontrollable, recurring thoughts — such as a disproportionate fear of germs — and behavior she or he feels compelled to repeat over and over, such as excessive hand-washing.

Impulse-control disorders, on the other hand, typically involve an inability to resist a potentially harmful or self-destructive urge.

An estimated 2 percent to 5 percent of Americans suffer from hair pulling (which includes eyelash pulling) and 5 percent from skin picking, the two most-common body-focused repetitive behaviors, according to the TLC Foundation for Body-Focused Repetitive Behaviors. Others include hair or skin eating, lip and cheek biting, tongue chewing and compulsive hair-cutting, according to the foundation, a nonprofit based in Santa Cruz, California.

Before age 12, hair pulling occurs equally in boys and girls, but later it predominantly occurs in girls, according to psychologist Suzanne Mouton-Odum, a clinical assistant professor at the Baylor College of Medicine. “Why is this? We are not certain, but I suspect that many more females begin to pull around the age of puberty,” she says. “Likely there is a hormonal component that affects more females than males. Other hypotheses are that males are more able to cover hair loss, or maybe do not seek treatment as they can hide the results of their pulling.”

Researchers believe that these disorders probably have a genetic component, because they tend to run in families. Scientists are studying the genes of affected people, trying to identify markers that can provide clues to their origins. Several studies have shown a familial connection; one, for example, found higher rates of OCD in immediate family members of those with extreme cases of hair pulling than in the general population.

Also, evidence from a twins study suggested a higher occurrence of hair pulling in identical compared with fraternal twins. Research also has shown differences in the brains of people with these disorders compared with the brains of those who don’t have them.

“Each person seems to pull or pick for different reasons, or in different situations,” Mouton-Odum says. “Some do it in response to emotion — anger, anxiety, happiness — while others in response to needing to feel a certain sensory sensation, while others pull or pick in response to certain environmental triggers, such as activities, places, mirrors.”

Woods agrees. “The behaviors seem to be both a problem of a habit gone awry and a way of coping with emotional distress,” he says.

Medication such as clomipramine, an antidepressant used to treat OCD, can help, but experts say the most effective therapy is behavioral. There are two frequently used approaches.

The first is habit-reversal training, which teaches patients to be more aware of their pulling and picking, and its cues, and trains them to use a “competing response” when the urge hits, such as clenching the fist with the hair-pulling hand and pressing it to the side of the body.

The second is comprehensive behavioral treatment, which “looks at each person as an individual and evaluates (his or her) individual pulling/picking profile,” Mouton-Odum says. Behavioral treatment allows clinicians to design a treatment plan specifically for that person. “Strategies are offered based upon their unique pulling/picking triggers,” she adds. “It is not a one-size-fits-all approach. It is quite tailored.”

Because people often are unaware of when they pull or pick, some have found that using an app-equipped bracelet called Keen helps control the habit.

The bracelets are programmed to detect when the behaviors begin, then send a gentle vibration to alert the individual to stop. The bracelet has not been studied in clinical trials, but anecdotal reports suggest it can be a valuable tool. Its price starts at $129.

Lesley Stevens, 37, an online content creator who lives near Phoenix, is a hair puller, skin picker, nail biter and thumb sucker. She wears one bracelet on each wrist — because she picks and pulls with both hands — and says they have been very useful in keeping her habits under control. “They buzz my wrist and make me aware when I’m doing anything I have trained it for,” she says.

For Harper, the Texas teenager, connecting with other body-focused repetitive behaviors people “who completely understand my struggles” has enabled her to cope, as has attending therapy workshops.

She says she still struggles “a little” with skin-picking, “but it doesn’t control my life anymore, and being open about it allows me to not be ashamed,” she says.